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Full Discussion: Overwrite
Top Forums UNIX for Dummies Questions & Answers Overwrite Post 1714 by PxT on Tuesday 27th of March 2001 12:27:32 AM
Old 03-27-2001
Quote:
what is the noclobber variable? what does it do?

If you turn on the noclobber option with "set noclobber" then redirecting to an existing file using the > should produce an error. In csh/tcsh this can be overridden on a case-by-case basis with >!, in bash/ksh it is >|

In csh/tcsh you also have the &gt;&gt;! syntax. If noclobber is set, and you use &gt;&gt; to append to a file, you will get an error if the file does <I>not exist</I> (can't append to a non-existant file). If you use &gt;&gt;! you will override this behaviour, and create the file if it does not already exist. I dont believe that bash or ksh have this feature (file is always created if it does not exist).

noclobber is a handy option if you tend to frequently overwrite files that you intended to keep. See the relevant manual page for your shell to learn more about this and other options.



[Edited by PxT on 03-27-2001 at 12:34 AM]
 

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LEARN ABOUT SUNOS

shells

shells(4)							   File Formats 							 shells(4)

NAME

       shells - shell database

SYNOPSIS

       /etc/shells

DESCRIPTION

       The shells file contains a list of the shells on the system. Applications use this file to determine whether a shell is valid. See getuser-
       shell(3C). For each shell a single line should be present, consisting of the shell's path, relative to root.

       A hash mark (#) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by  the  routines
       which search the file. Blank lines are also ignored.

       The  following  default	shells are used by utilities: /bin/bash, /bin/csh, /bin/jsh, /bin/ksh, /bin/pfcsh, /bin/pfksh, /bin/pfsh, /bin/sh,
       /bin/tcsh,  /bin/zsh,  /sbin/jsh,  /sbin/sh,  /usr/bin/bash,  /usr/bin/csh,  /usr/bin/jsh,  /usr/bin/ksh,  /usr/bin/pfcsh,  /usr/bin/pfksh,
       /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh. Note that /etc/shells overrides the default list.

       Invalid shells in /etc/shells may cause unexpected behavior (such as being unable to log in by way of ftp(1)).

FILES

       /etc/shells	       lists shells on system

SEE ALSO

       vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4)

SunOS 5.10							    4 Jun 2001								 shells(4)
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